Lifting mechanism



Nov. 25, 1930. J. DOLAN LIFTING MECHANISM Filed Oct. 17, 1927 2 Sheets-Sheet 1 I lNl/EA/TOH.

Arron/0 zobility. i

Patented Non. 25,1930

This'hinnentien qrelatesl te lifting' nae/cilia nisins and-is designed' more partienl'arly for nselin lifting jacksfl relatively lrnonable' lifting :ine' nbers with a means for controlling the relative movements of said members. 1.

j -Afnrther bje0t 'of the invention to prei0 vide sue-h adevieein which both lifting mein:

bersmay be provided With teethofja Width Substantially u o the width of thenonter lifting member. f i 1 I :A further object of; the intentienis tepre- -VideJsucha lifting mechanism havingtelescoping lifting members so constructed and arranged asto provide a lifting, "eleinentwhich will be simple in its construction and which will have greatstrength and: duravide; su ch lifting "mechanism with 'IIlBELIlS whereby, the'lifting element may be operated atdiflerent speeds at the'will of the operator.

Other objects ofthe inventionwillappear] as the mechanism is described indetail. u l

l In.theaccompanying"drawingsFig 1 is a side. elevatiemjpartly injsection, of a; lifting jack: embody ng my nvention ;.Fig. 2 1s a side 1 partly inelevationyand partly ingsectio'n, showing the lifting nenibers'in extended p0- sitions; Fig. 3isxa secti0nalview1taken onthe.

pawl; and Fig B isavertical sectiontake i 4 thron I the i lifting members and shbwing theinner meinberln ts elevated posltion.

Ingthese drawingsllhaveiillustrated one enibedi nentqf ny inventlenand have shown the same as applied to an autd'inobile J ack but it will be understand that thein-echanism ina yt take variousformsand inaybentiliz ed,

with lifting mechanisms of various kinds withentdeparting from" the spirit oflthe in ventiont l hni mbq m n lherei sto e ei ck a ine mem s.

elevationbf the "upper portion of the-j aek,

enter 'lifting niember and ;is rigidly secured, n la g vefilinvt e bQdXIPQr' -bn 1 inn r m t lh t n u Q th s QQW a21arepreferably'doyegtailed and a Pin 22 ex tending throngh the {same and athrouglritlie adjacent,portionsfofxthe part1? serves tel v comprissaubase 10havingflrigidlyi secured theretoanupvvandly extending hollowstande" t v 71 l L 1 andilL-p Slidably mountecl i ithis standardis uQne object a of the invention is t0 provide" f awlifting mechanism ha'vingarplurality Of a lifting felementflwhich preferablyQ consists IOftWQ relatively movable t l d i members V V 1 12;. (and: fits snugly between theside walls of the standard 11. ,This iouter member is; pro;-

vided with a longitiidinally extending guideway, which opens :throughone of the side Walls thereof. This outer lifting member may be a formed in variousways but I prefer t0utilize a barflof: metal of -theproper dimensions and; to, provide thesame with a longitudinalbore arranged substantially centrally thereof, as

'shewn:iatl8, and toithen cut away one wall of the" member, in the present instance the rear "walh-teulprovide a"verticalpopening 14 If i 1 l h, 1 desired, the edges 15yofthisenter member m Affnrtherobjectlof the invention is to prd,

on6pp0site sides of the opening 14;; may he beveled, o'tlfiared outwardly. The outer liftingmemberlQ is provided onitha't side oppd,

site theiepening 14 \with teeth 16 extending;

inner lifting member; this cylindrical por- 1 tion having asliding fit inttheaboreofithen outer ineniben; Rigidlyfsecured 'tq the body 180 portion-11? 0f the inner. member; is a rank 7 ha-r18, As -here shown, thislwkbar is offa' Width substantiallyfequal to the widthef'the outer nie'rnber 12, hasaon-iitsonter fa'ee teeth 19 extendingjfbr the fnllwidth thereof and 8 5; thasf on its'ylzinner; sideg'a lqngitndinally exa; V

nd n i ns e .i f r 0 which? exte ds hr ugh the; op n isti th r ar (Wal f he' "eonneetthe two parts of the inner liftingmemberbnetothdothr. The laterf} allyeXtending vportiens or flanges 'of the rack l 8lpreferablybear against'andhayeslidingc. in a movement on the edges lfiforthe guterliftg I ing; inenibier. this Twit-filler "1 am able ftb provide both the inner and outer lifting members with rack teeth of a transverse length equal to the width of the outer lifting member, thus providing those teeth with a largedegree of strength. The construction of the lifting element is such that the parts may be easily manufactured and assembled and when assembled will be of a very strong durable character.

It will be noted that the teeth of the two lifting members are arranged on the opposite sides of the lifting element as a whole and the two lifting members are operated by pinions 23 and 24, respectively, which are mounted on shafts 25 and 26 journaled in suitable bearings on the standard 11. These pinions are arranged near the upper end of the standard and the front and rear walls of the standard are cut away to provide openings through which the pinions extend to enable them to mesh with the respective rack teeth. The pinions may be operated in any suitable manner but, in the present instance, they are rotated simultaneously from a common source of power and to this end intermeshing gears 27 and 28, of the same diameter, are mounted on the shafts 25 and 26, and secured to one of these shafts, in the present instance the shaft 25, is a worm wheel 29 constituting a driving element forthe rack operating pinions and which is driven in a manner hereinafter described. Preferably one of the lifting members if elevated to the upper limit of its movement before the other lifting member is actuated. In the present instance, the inner lifting member is first operated and the outer lifting member is so controlled that it will have no vertical movement until the inner lifting member has completed its upward movement with relation thereto, and will then be actuated, the inner member being then locked to the outer memher to retain it in its extended position with relation thereto. As has been stated, the actuating pinions 23 and 2 1 are rotated simultaneously and to prevent the movement of the outer member during the initial movement of the inner member the teeth 16 of the outer member terminate just below the pinion 24 so that when the outer member is in its lowermost position the pinion 2 1 can rotate withoutengaging the teeth. Consequently when the actuating pinions are retated the inner member only will be elevated. Means are provided for moving the outer lifting member upwardly, after the inner;

member has reached its limit of movement with relation thereto, to cause the teeth 16 to be moved into operative relation to the pinion 24. This may be accomplished in various ways but, as here shown, the body 1'7 of the innermember has a second vertical groove 30, the lower end of which forms a stop, as shown at 31. Rigidly secured to the outer member, near the upper end thereof, and extending into the groove 30, is a projection, such as a block 32, so arranged that as the inner member reaches the upper limit of its movement with relation to the outer member the stop 31 will engage the block 32 and the further movement of the inner member by its pinion 23 will cause the outer member to move with it, thereby carrying the teeth 16 into mesh with the pinion 24. After the pinion 24 is in mesh with the teeth 16 the teeth 19 move out of mesh with the pinion 23, and the two lifting members are moved upwardly simultaneously by the pinion 24. It will be obvious that the groove 30 may be formed in either member and the projection carried by the other member.

Any suitable means may be provided for locking the inner member in its extended position with relation to the outer member but it is important that this mechanism should be positively controlled to prevent the accidental release of the inner member and the dropping of the load. As here shown, the locking means comprises a pawl 33 rigidly secured to a shaft 34 journaled in suitable bearings in an enlarged upper portion or collar 35 carried by theouter member, this collar being recessed to receive the pawl 33 and to permit the same to be moved into and out of locking engagement with the teeth 19 of the rack bar 18. Rigidly secured to the shaft 34, at one side of the collar 35, is an actuating arm comprising an upper portion 36 and a lower portion 37. The upper portion of the arm is acted upon by a s oring 38 which tends to rock the shaft 34 in a direction to cause the pawl 3 to engage the teeth 19. The lower portion 37 of the pawl actuating arm is preferably curved and may, if desired, be tapered as shown in Fig. 1. Rigidly secured to the standard 11 are two projections or studs 38 and 39 which are so arranged that when the outer lifting member is in its lowermost position the portion 37 of the actuating arm will lie between these studs and the lower end thereof will extend beneath the stud 38. When an upward movement is imparted to the outer lifting member the arm 37 will ride over the stud 38, thus causing the shaft 34 to be rocked in a direction to move the pawl into locking position, in. which position it will be held by the spring 38 V] hen the outer lifting member moves downwardly and approaches its lowermost position the outer edge of the part 37 of the actuating arm will engage and ride over the stud 39, thus rocking the shaft 34 to move the pawl out of engagement with the teeth of the inner lifting member and releasing that member so thatit can move downwardly with relation to the outer member. While the spring 38 would ordinarily hold the pawl in its operative position I prefer to provide a positive lock for that pawl and I-have therefore provided the pawl thevspringi38 -isgcomiected with the arml and acts =hoth on tha-tia-iivn i aii'dllon theapawl" actuating; arm. The lower end of. the look= mg; arm: :41 ris bev ele'cl and arranged to en- I gagela" projection or stud 43 on theistahdard 11s when the outer lifting member approaches its lowermost position, thereby causing the locking member to he er noved forwardly to disengage theproj ectionLZfnoIn the-finger 4:0

and release the pawl actuating arm fomhove inen't by the stud 39-, the} arran'gementof the stii'ds'itii iand 39" being' siiohfithat thearm 41 will bje operated betore the arm 37 "engages the stud '39. Whehxgthe oiiterfiliftingment her inovesiupwardly the arm" 42 Will-move out of jengagement'with the stud i3 after the ame 37111211; been actuatecla'by the stud 88 110 m ove the-pawl33f to locking position, thus permitting theproj ection 42 of the arm l to Opelfk tively engagefthe fiiigeriitO. 1 f i 1T0 prevent thepossihil-i-tyofthe outer lifting member heihg dragged upwafclly the inner liftiiigjiiiember'; and time 'causmg its teeth to engage the ooperating pinioh'before the inner niemhei has- -conipletedflits 'movewent; I have pi ovided a "Fiock which" pos tively I prevent the iipwald I [movement of t m outei' iiienibef 'biitwvhioh will he; aiitoy lil il lifially relea ed beforet-he inner member teaches the upper lih'iitof its-movement with relatiensto the outer member; As ,shojwnwir F ,Tthi's' loekinggme berice rises arih 4 k 'pivotal ly mounted on the outer liftf injgineniher arid *hjaviiig a nose {45 to engage a normally irtjits opeiative position, ten ing i eai wardly' item the arm: M 183 48f ai'tanged tohe engaged theQIaterQ extending iqoiftion 49 ot a, nod 50 which i s n thmue i. a outer member and hasdyertioal poi tion slidablylmmmted in aQguicie ay inwthe'pm,

"(1 "extending below, the p foj'ece a slot jl jthe sidewall ofthe of thatg rooyegthe stop 3i, just hefoigeithat stop; enga es-the, Ptoj ectiori, tl iuspatisiiig y the lock to he ,iiioved to: its 1 inoperative positlon itetore the .i nei [member isco neCted with the outer memher;

,wortn ee rr ed by e-e e t 52 a-iw ml a l- 1 ib e'r eee l m m efiend-(item d, I i e d the t et 1 or egs 6&91 he hT-m m e ie euelws e that they illxim being" formed iin t epre ent inet mesiin Jane walletaig arneafiingififi EIh WQrm-may'be uatedinanysuitable mann r butil pm i sequently vlif ing? e nentymay :be aperate'd at difierentspeeds at the will pfzthe op-1 erator; Tothi'sienct Lhaxze here shownle see- 0nd shaft fikmourtted 'inra heari-ng 15f ginithe forwards-Wa l Q ege masi gt55 iandtedwpt ed to e eonneeteds with "a suit l opemti g d i l a t lic anky: and ri iterpesed e mul iplyingigeaxzingiwh ehm y be tonne te with 017 disconnected from the shaft 56; 813

will. As here shown, the forward endofthe h f 52tisah l owl andith tea e s f th shaft:56 extends into andxis rotatahlyt aj d slidably mounted in --the hollow; end portion of the shaft 52. Rigidly secunedtothe slhaft 52 is. a {pinion 58 which mesheswith ;-;a 1 gear; 301 h t 0, e180 :iml i a edl -theg e -t easing. 1A pinion {6 1 pigidly secured tot-the shaft 60 meshes'with a gear 62 whichiis rloosely mounted on the shaft-J56. secured to the gears 58 anfdf62 are :cluth: imenihel's 3 r hi jewi ti d Q which'imi spaced apart V Rigidlyjseou-red to thelehett 56 is-a'c1utch memberz65 wh ehisiadapted, to:

operativelyl engage eithen of the clutch IIlBm-I shaft 52 aetsgon the endt ofthe shaft 56 to '95; hers63 and 64. A spring 66 in the-Q-hollow move that shaft outwardlyand thus aholjcl the i clutchfmember 65 normally; in operativeengagement with the clutoh member 64. \Nith the clutch in this position the ,rotatimofih shaft 56Wi11 betransmitted to the shaft52 through the multiplying geai'ingand-tlm WOBIII I ar d lifting element will be operated at a high :speed By pressing inwardly on the shaft56 the clutch membet' 65 may be disconnected from the olutch meinher M'andco h nected with the elutoh memhei fiithus estab+ lishing a direct connection-between the shaft 56 andthe shaft 52 andvoausing the latter togirotate atthe same speed; asthe sha t't 56,

the gear train running idle during thisdine'qt connec i n alt wil he! eni en eefin th teftbt -t tie k pla e i R si l lenw h tin eleme t m y e op ra e t high speed to run the it same :quiekl inf speect t Clutches I haye s0 eenstrueteg1 the members that -they will: Joe locked jii niiengagement, one;

r t t a. M1 31 en a 'e i entiwith the work .and hy ithen shi fb i he elutoh .it may be @PQLflitGdiLt aleWer lift ithe-load. Likewise the -li;f ti11g ele ent; meya e mdre er at ih e spe c1 A I s l onetlow speed. :vfBhe;clutchmembeis may 1;he,engag'ed by the bottom with theiotheig: fl e this endltheislots fii in V through the narrow portions of the T-shaped slots and when the shaft 56 is rotated will be moved behind the shoulders at those sides of the slots toward which the shaft is rotated. Thus the clutch member 65 will be held in engagement with the other clutch member until the shaft is rotated in a reverse direction to bring the teeth68 into line with the narrow portions of theT-shaped slots.

lVhile I have shown and described one embodiment of my invention Ido not desire to be limited to the details thereof as various modifications may occur to a person skilled in the art. r 7

Having now fully described my invention, what I claim as new and desire to secure by Letters Patent, is:

1. In a lifting mechanism, a hollow standard, an outer lifting member mounted for vertical movement in said standard, having teeth on one side thereof and having a longitudinal guideway opening through the other side thereof, an inner lifting member slidably mounted in said'guideway and having a part extending beyond said guideway and overlapping the edges ofsaid outermember at the sides of said guideway, said part of said inner lifting member having teeth on the outer side thereof, separate pinions to engage the teeth on the respective lifting members, and means to actuate said pinions.

2. In a lifting mechanism, a hollow standard, an outer lifting member mounted in said standard for vertical movement, having teeth on one side thereof, having a longitudinal guideway therein, and having an opening through another side thereof, said opening being of a width less than the width of said guideway, an inner lifting member having a part slidably mounted in said guideway, and a part extending through said longitudinal opening and having'fianges whichoverlap the edges of said outer member on the respective sides of said opening, said flanged part having teeth on the outer sidethereof, pinions to engage the teeth on'the respective members, and means for actuating said pinions.

3. In a lifting mechanism, a hollow standard, an outer lifting member mounted in said standard for vertical movement, having teeth on one side thereof and having a longitudinal cylindrical bore and also having a longitudinal opening through another side thereof, an inner lifting member comprising a cylindrical part slidably mounted ,in the bore of the first mentioned member,a rack bar of a width substantially'equal to the width of said outer member, having teeth on its outer side and having a part extending through said opening in said outer lifting member and rigidly secured to the first mentioned part of said inner member, said standard having openings in the Walls thereof near its upper end, pinions rotatably mounted on said standard and extending through said openings-to engage the teeth on the respective lifting members, and means for actuating said pinions.

4. In a lifting mechanism, a hollow standard, an outer lifting member mounted in said standard for vertical movement, having teeth on one side thereof and having a longitudinal cylindrical bore and also having a longitudinal opening through another side thereof, an inner lifting member comprising a cylindrical part slidably mounted in the bore of the first mentioned member, a rack bar of a width substantially equal to the width of said outer member, having teeth on its outer side'and having a part extending through said opening in said outer lifting member and rigidly secured to the first mentioned part of said inner member, said cylindrical portion of said inner member having a longitudinal groove therein and a stop at the lower end of said groove, and said outer member having a part projecting into said groove and adapted to be engaged by said stop to impart initial movement to said outer member, pinions to engage the teeth on the respective lifting members, the pinion for the outer lifting member being so arranged that it will be out of engagement with the teeth of that lifting member when the latter is in its lowermost position, and means for actuating said pinions.

5. In a lifting mechanism, a hollow standard, an outer lifting member mounted in said standard for vertical movement, an inner lifting member mounted within said outer lifting member, means for first moving said inner lifting member to its uppermost position with relation to said outer lifting member and for then imparting movement to said outer lifting member, a locking member carried by said outer lifting member and movable into and out of locking engagement with the inner lifting member, an actuating arm connected with said locking member and having a curved lower portion, and parts carried by said standard to engage said curved portion of said arm and move said locking member into locking position when said outer lifting member is moved upwardly and to engage said curved portion of said actuating arm and move said locking member into its inoperative position, when said outer lifting member approaches the lower limit of its movement. a

6. In a lifting mechanism, a hollow standard, an outer lifting member mounted within said standard for vertical movement and having teeth on one side thereof, an inner lifting member mounted within said outer lifting member for vertical movement with relation thereto and having teeth on one side thereof, pinions carried by said standard to engage the teeth of the respective lifting members, the pinion for the outer liftmember being so arranged that it will 1 qbejoutof engagement with the teeth thereof when saidouter liftingmemberis inits lowermost'ipositionymeans {for movingnthe ;teeth"of s ald outerllftmg member into en- ,gagement withsaid pinion when said inner ilifting, member has completed movement x {with relation to said outer lifting member, a

pawl mounted-on saidouter lifting member I for {movement into; and out of engagement 1 with the teeth .of; said inner lifting member,

*8 an actuating-arm rigidly connected withsaid I i .pawl and; having a. curved lower end,- pins carriediby zsaidstandardand so arranged on that whenqsaid outer lifting memberis.

moved upwardly from itSRlOWGImOSt posi- 1 tion said actuating arm will'be movedin a directionto move the pawl into; engagement ;,with said teeth and: when? said outer liftlng member approaches the lower limit of jmoyeme'ntflsaid actuating arm will be movedin a directionitomove said pawl out (of engagement; with" said teeth. 3 i '7. In alifting mechanism, ah W within said standard for vertical movew Sana- H rd-5 1 3111 outer 1 lifting; member mounted:

:ment; wand having kj teethon '1 one side;

\ thereof, tan inner Y lifting member mounted within said outer lifting member for verti- "cal movement- Withrelation thereto and having teeth won f oneixside thereof, pinions cara ried by; {said standard"; to engage the? 1 teeth ofthe respective lifting membersflhe pinion J for it thew outer lifting member being; so ar- 1- 3 V i i with thete'ethw thereof when saidouter liftrangedf thatit will beIoutofengagementx Xing-member is in its lowermost position, meansforumoVing the teeth-,of said-router 1 lifting member into engagement Wltll sald pinion whenwsaid inner lifting member. has i i i completed iits movement with relation-toisaid outer lifting member, a pawl -mounted'on "L said outer lifting 'member for movementrinto 'andbut 'of engagement with the'teethof said inner lifting member," an n-iactuating arm rigidly connected with said pawl and having a i curved lower end, pinscarried'by saidstand ard and it so arranged that when saidouter liftingmember is moved upwardly fromits JIOWQIIIIOStrpOSItIO H, said actuating arm will a be -moved in i a direction to i move the pawl} into engagement: with said teeth, and i when 1 said outer lifting member approaches: the lower limit-of its movement said actuating} arm :will be;- moved in ae directionto move 1 I said pawloutof: engagement with said teeth,

i a-=locking:memberqcarriedby:said'outer-'liftin am mberand arranged-toengageiapart carriedabygsaid actuating armhnd retain =saidlocking 5 pawl inengagement-with said e e teeth,- and means for:moving said locking a:

1 member into "aH'HIOPlEIatIVQ POSltlOlT as-sa1d i outer lifti member ap proaches the lower 1 1 815111; ailiftingfmechanism, hollow standlard, an outer lifting membermounted in gsaidi standard for; vertical movement,. an :innerrliftmg member mounted n said outer lifting member for vertical movementrlwith relation thereto, means for moving said] in} mentfwith relation to said outer lifting member andthenampartm-g movement to said outer lifting member, a locking member carriedyby said outer lifting niemberiand mow able into and out ofv a position to lock-said inner lifting member in V its extended post her, "fan actuating arm connected with :said locking member, means carried by said. standardtdmove said actuating arm n one ner llftlng member to the l1m1t. of 1tsmovetion with relation to said-outer liftingimemdirection when upward, movement is imparted to said outer lifting member, and to I move saidactuating armin the other direc- ,tlQIl as saidgouter lifting member approaches,

the lower limit of its movemennajfinger se V cured to said actuating arm, an arm movably mounted onsaid outer lifting member and, having a part adapted-to engage rsaid finger. to, retain said locking member in its locking, position, and a part carried 'by said standard ;to -move said arm-out .of engagement with saidfinger as said outer lifting member approaches its F-lowermost position.

*9. In a lifting mechanism, a standard,,a toothed liftingmember mounted for vertical movement withrelationtol said standard, a

pinion t'o (actuate said-lifting member, means for operatingsaid,pinion? at diiferent speeds comprising a shaft operatively; jconnected y with l said pinion, a second @shaft, multiplying gearingyjconnectedwith oneofsai-d shafts, and\ineansfor connecting said-j gearing ,w th

the othershaft'iior for connecting-lsaid-sec i v with the rfirsa mentioned; 5

connecting the first mentioned q gears; 2 and means controlledby the axial movement" ]of same either directly with the first mentioned shaft or wit'hthat gear which is loosely mountedon thelast mentioned cshaft. r I

ting mechanism, a standard, a

-l saidlast mentioned yw shaft tojconnectlthe 1 1.-Ina liftingmechanism, a standard, a toothed lifting member mounted for vertical movement with relation to said standard, a pinion to'actuate said lifting member,-means for op eratingsaid pinion at zdifierent speeds comprising a shaft operatively connected with said pinion, a second shaft arranged in axial alinement with the first mentioned shaft and capable of both axial and rotatory movement with relation thereto, a gear rigidly secured to the first mentioned shaft, a second gear rotatably mounted on the last mentioned shaft, intermediate gears connecting the first mentioned gears, and clutch members secured to the two first mentioned gears, a clutch member rigidly secured to the last mentioned shaft and adapted to be moved into operative engagement with either of the first mentionedclutch members by the axial movement of said shaft.

12. In a lifting mechanism, a standard, a toothed lifting member mounted for vertical movement with relation to said standard, a pinion to actuate said lifting member, means for operating said pinion at different speeds comprising a shaft operatively connected with said pinion, a second shaft arranged in axial alinement with the first mentioned shaft and capable of both axial and rotatory movement with relation thereto, a gear rigidly secured to the first mentioned'shaft, a second gear rotatably mounted on the last mentioned shaft, intermediate gears connecting the first mentioned gears, clutch members secured to the two first mentioned gears, a clutch member rigidly secured to the last mentioned shaft and adapted to be moved into operative engagement with either of the first mentioned clutch members by the axial movement of said shaft, and a spring tending to hold the last mentioned clutch member in operative engagement with that clutch member which is carried by the gear loosely mounted on the lastmentioned shaft 13. In a lifting mechanism, a hollow standard, a toothed lifting member mounted in said standard for vertical movement, a pinion carried by said standard and adapted to engage the teeth of said lifting member, a worm wheel: connected with said pinion, a shaft journaled on said standard, a worm carried by said shaft and meshing with said worm wheel, a second shaft mounted on said standard for axial movement, a gear rigidly secured to said worm shaft, a second gear loosely mounted on said second shaft and having geared connection with the first mentioned gear, a clutch mechanism; controlled by the axial movement of said second shaft to connect the same either directly with the first mentioned shaft or with the gear which is loosely mounted on said second shaft.

14. In a lifting mechanism, a hollow standard, a toothed lifting member mounted in said standard for vertical movement, a pinion carried by said standard and adapted to engage the teeth of said lifting memher, a worm wheel connected with said pinlOI]. a hollow shaft journaled on sa standard, a Worm secured to said shaft and meshing with said worm wheel, a second shaft journaled on said standard and having one end rotatably and slidably mounted in said hollow shaft, a gear rigidly secured to said hollow shaft, a second gear rotatably mounted on said second shaft and having geared connection with the first mentioned gear, said first mentioned gear and said second gear being spaced one from the other, clutch mem bers secured to'the adjacent faces of said gears, and a clutch member secured to said second shaft between said gears for movement into operative engagement with either of the first mentioned clutch members. 15. In a lifting mechanism, a hollow standard, a toothed lifting member mounted in said standard for vertical movement, a pinion carried by said standard and adapted to engage the teeth of said lifting member," a worm wheel connected with said pinion, a hollow shaft journaled on said standard, a worm secured to said shaft and meshing with said worm wheel,'a second shaft journaled on said standard and having one end rotatably and slidably mounted in said hollow shaft, a gear rigidly secured to said hollow shaft, a second gear rotatably mounted on said second shaft and having geared connection with the first mentioned gear, said first mentioned gear and said second gear being spaced one from the other. clutch members secured to the adjacent faces of said gears, and a clutch member secured to said second shaft between said gears for movement into operative engagement with either of the first mentioned clutch members, and a spring mounted in said hollow shaft and acting on said second shaft to hold the last mentioned clutch member normally in en gagement with one of the first mentioned clutch members. 16. In a lifting mechanism, a hollow standard, an outer lifting member mounted in said standard for vertical movement and having teeth on one side thereof, an inner lifting member mounted in said outer lifting member for vertical movement and having teeth on that side thereof opposite the toothed side of the outer lifting member, pinions carried by said standard and arranged to engage the teeth of the respective lifting members, the pinion for the outer lifting member being so arranged that it will be out of engagement with the teeth of that member when the latter is in its lowermost position, means for actuating said pinions whereby one of said pinions will impart movement to said inner lifting member with relation to said outer lift ing member. a locking member carried by said outer lifting member and adapted to engage a part of said standard to hold said outer lifting member against vertical movement, an actuating member having one end arranged in operative relation to said lock 111; member, and means carried by said inner lifting member to engage the other end of said actuating member as said inner lifting member approaches the upper limit of its movement with relationto said outer lifting" member and move said locking member to an inoperative position and to impart initial movement to-said outer lifting member after said locking member has been moved toits inoperative position. I

17. In a lifting mechanism, a standard, a toothed member mounted for vertical movement with relation to said stand'ard,a pinion i r i to actuate saidlifting member, a shaft 0p 1 eratively connected with said pinion, a second shaft to actuate the firstmentioned shaft, said second shaft being mounted for both rotary and axial movement, a variable speed meehanism for connecting said secondshaft with said first mentioned shaft and comprising means actuated by the axial movement of said 11 a second shaft to control the speed at which said 7 pinion is rotated.

I testimony whereof, I aflixmy signature IJOXHNDYOLAYN.

hereto. 

